• Tribology and Lubricants
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• v.30 no.1
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• pp.36-45
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• 2014

Understanding steel/skin contact phenomena is important for the study of object manipulation in robotics and has been a topic of great interest. In this study, pig skin was taken as a surrogate model for human skin, and its adhesive, friction, and deformation behaviors were measured under various exposure times to air. Indentation, friction, and scratch tests were performed at $25^{\circ}C$ and 45% relative humidity. The influences of adhesion and deformation on the coefficient of friction were characterized; the pig skin was found to be sensitive to the sliding velocity and normal load under the controlled experimental conditions.

• Science of Emotion and Sensibility
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• v.16 no.3
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• pp.311-318
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• 2013

This research examined the validity of whether the PMV index-based comfort- or uncomfort-indoor environments could be classified by the facial skin temperature, one of the physiological indicator for human. To do this, we distinguished between a comfort thermal environment and an uncomfort thermal environment using the PMV value, and then facial skin temperatures were measured in both environments. As a result, the facial skin temperature of occupants were different between the comfort- and uncomfort-indoor environments. It suggested that the facial skin temperature could be used in shaping the comfortable indoor environment based on the PMV index. While this result suggested the PMV index-based on comfort and uncomfort indoor environments could not be valid, because the facial skin temperature was lower in the uncomfort thermal environment than in the comfort thermal environment.

• Archives of Plastic Surgery
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• v.33 no.5
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• pp.606-611
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• 2006

Purpose: Animal models of a chronic wound are yet to be fully developed, and animal studies on this subject has yet to take place. The purpose of this study is to create the foundation for research on chronic wound healing based on a swine model, the most similar to that of a human. Methods: Three female 2-3 month old 'yolkshires' were used. Total of eight full thickness skin defects, $6{\times}3cm$ sized, were created on the back of each pigs. Three groups were created for comparison; Group I (n=4) was left as they were after full skin thickness excision, while the excised tissues of Group II (n=3) were turned inside out and sutured so that the epidermis would come in contact with the fascia. Group III (n=3) were excised full skin thickness in depth and silicone blocks were implanted in them. Dressing was not practised so that the wounds would be vulnerable to infection. Results: In Group III, the skin contraction rate was the least among the three groups for each three weeks of observation respectively. Also during the three weeks, bacteral colonization was at the highest among the comparison. On the third week, inflammatory cells were still active, but the generations of epidermis and collagen synthesis were detected minimally. Conclusion: The Group III was relatively the most similar model of chronic wounds. and modification of the silicone blocks, could provide us with a very effective chronic skin wound model similar to human.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.45-45
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• 2003

Human papillomavirus type 16(HPV16) has been known to the major factor for the development of uterine cervical carcinomas. We have extended these studies to investigate the in vivo activities of HPV-16 E6/E7 when expressed in squamous epithelia of transgenic mice. Grossly, hK14HPV16E6/E7 transgenic mice had multiple phenotypes, including wrinkled skin that was apparent prior to the appearance of hair on neonates, thickened ears, and loss of hair in adults. In the transgenic mice, the wrinkled skin phenotype on the body and legs died at the age of 3∼4 weeks. Histological analysis of demonstrated that E6/E7 causes epidermal hyperplasia in multiple transgenic lineages with high penetrance. This epithelial hyperplasia was characterized by an expansion of the proliferating compartment and an expansion of the keratinocyte and was associated with hyperkeratosis. These transgenic mice expressed E6/E7 transgene mainly in skin, heart, pancreas and kidney. Hyperplasia was found at the skin. The enzyme activities of GR, GPx and CuZnSOD were measured from the transgene cause keratinocyte at the skin. The specific enzyme activities were significantly higher in transgenic mice skin compared to the normal mice skin. Thus these transgenic mice may be useful for the develpment of antioxidant enzymes or other therapies for HPV-associated hyperkeratosis.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.3
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• pp.243-252
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• 2020

Using Fervidobacterium islandicum AW-1, polar low molecular weight keratin peptides were produced and confirmed through factors related to the skin elasticity. As a result of confirming the cytotoxicity and collagen synthesis ability according to the concentration of the polar low molecular weight keratin peptide in human fibroblasts, it was confirmed that the cytotoxicity did not appear and the collagen synthesis in human fibroblasts was increased. A mask pack containing a polar low-molecular weight keratin peptide was used, and a test product was used for 4 weeks in 22 healthy women subjects. As a result, it showed statistically significant effects on skin elasticity, skin torsion elasticity, skin color and moisture improvement. Through this test, it was confirmed that the polar low-molecular keratin peptide can be used as a cosmetic ingredient that helps improve skin elasticity.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1583-1591
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• 2014

Ultraviolet (UV) irradiation alters multiple molecular pathways in the skin, thereby inducing skin damage, including photoaging. In recent years, probiotics have gained interest due to their beneficial effects on skin health, such as inhibiting atopic dermatitis and improving skin immunity or inflammation. However, little is known about the effects of probiotics on UVB-induced photoaging. In this study, we evaluated the effect of Lactobacillus plantarum HY7714 against UVB-induced photoaging in human dermal fibroblasts and hairless mice. The results showed that L. plantarum HY7714 treatment effectively rescued UVB-reduced procollagen expression through the inhibition of UVB-induced matrix metalloproteinase (MMP)-1 expression in human dermal fibroblasts. Data from a western blot showed that L. plantarum HY7714 inhibited the phosphorylation of Jun N-terminal kinase, thereby suppressing the UVB-induced phosphorylation and expression of c-Jun. Oral administration of L. plantarum HY7714 clearly inhibited the number, depth, and area of wrinkles in hairless mouse skin. Histological data showed that L. plantarum HY7714 significantly inhibited UVB-induced epidermal thickness in mice. Western blot and zymography data also revealed that L. plantarum HY7714 effectively inhibited MMP-13 expression as well as MMP-2 and -9 activities in dermal tissue. Collectively, these results provide further insight regarding the skin biological actions of L. plantarum HY7714, a potential skin anti-photoaging agent.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.127-134
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• 2015

We investigated the growth-inhibitory activities of cosmetics and their preservatives against pathogens and resident skin bacteria. Of the tested cosmetics, preservatives such as parabens, 1,2-hexanediol, phenoxyethanol-contained toner, emulsion, cream and baby cream exhibited potent antibacterial effects against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Parabens, 1,2-hexanediol and phenoxyethanol inhibited the growth of pathogens, as well as skin-resident bacteria such as Staphilococcus epidermidis, Shigella flexneri, Enterobacter aerogenes and so on. The application of a basic cream containing phenoxyethanol to human skin was shown to disturb the skin microbiota: at the phylum level, Proteobacteria increased and at species level, 4P004125_s increased and Propionibacterium humerusii decreased. Based on these findings, parabens, 1,2-hexanediol and phenoxyethanol have antimicrobial activity and cosmetics containing phenoxyethanol may disturb skin microbiota.

• Nutrition Research and Practice
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• v.16 no.1
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• pp.1-13
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• 2022

BACKGROUND/OBJECTIVES: Bitter taste receptors are taste signaling pathway mediators, and are also expressed and function in extra-gustatory organs. Skin aging affects the quality of life and may lead to medical issues. The purpose of this study was to better understand the anti-skin aging effects of bitter taste receptors in D-galactose (D-gal)-induced aged human keratinocytes, HaCaT cells. MATERIALS/METHODS: Expressions of bitter taste receptors in HaCaT cells and mouse skin tissues were examined by polymerase chain reaction assay. Bitter taste receptor was overexpressed in HaCaT cells, and D-gal was treated to induce aging. We examined the effects of bitter taste receptors on aging by using β-galactosidase assay, wound healing assay, and Western blot assay. RESULTS: TAS2R16 and TAS2R10 were expressed in HaCaT cells and were upregulated by D-gal treatment. TAS2R16 exerted protective effects against skin aging by regulating p53 and p21, antioxidant enzymes, the SIRT1/mechanistic target of rapamycin pathway, cell migration, and epithelial-mesenchymal transition markers. TAS2R10 was further examined to confirm a role of TAS2R16 in cellular senescence and wound healing in D-gal-induced aged HaCaT cells. CONCLUSIONS: Our results suggest a novel potential preventive role of these receptors on skin aging by regulating cellular senescence and wound healing in human keratinocyte, HaCaT.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2004.11a
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• pp.17-17
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• 2004

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.43-49
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• 2005

Recently, according as people who have sensitive skin increase, we've been giving more importance to the safety of cosmetics. Especially, preservative is known to be one of the main stimuli which cause side-effects of cosmetics. However, there have been few reports describing cell cytotoxicity, skin penetration, oil-aqueous phase partition, anti-microbial activity of preservatives and their correlation with skin irritation. The study is aimed to develop low irritable preservative system with phenoxyethanol, one of the most commonly used preservatives in cosmetics, considering various factors mentioned above. According to our results of cell cytotoxicity against human normal fibroblasts by means of MTT assay, phenoxyethanol showed the lowest cytotoxicity when compared to other preservatives tested (cytotoxicity: pro-pylparaben > butylparaben > ethylparaben > methylparaben > triclosan > phenoxyethanol), but human patch test for assessing shin primary irritation revealed that phenoxyethanol has higher skin irritation than methylparaben and triclosan. We performed in vitro skin penetration test using horizontal Franz diffusion cells with skin membrane prepared from hairless mouse (5 ${\~}$ 8 weeks, male) to evaluate the rate of skin penetration of preservatives. From the results, we found that the higher irritable property of phenoxyethanol in human skin correlates with its predominant permeability (skin penetration: phenoxyethanol > methylparaben > ethylparaben > propylparaben > butylfaraben > triclosan). Therefore, we made an effort to reduce skin permeability of phenoxyethanol and found that not only the rate of skin penetration of phenoxyethanol but also its skin irritation is dramatically reduced in formulas containing oils with low polarity. In the experiments to investigate the effect of oil polarity on the oil-aqueous phase partition of phenoxyethanol, more than $70\%$ of phenoxyethanol was partitioned in aqueous phase in formulas containing oils with low polarity, while about $70 {\~} 90\%$ of phenoxyethanol was partitioned in oil phase in formulas containing oils with high polarity. Also, in aqueous phase phenoxyethanol showed greater anti-microbial activity. Conclusively, it appears that we can develop less toxic preservative system with reduced use dosage of phenox-yethanol and its skin penetration by changing oil composition in formulas.